Neural Basis Of Object Motion Perception During Self Motion
DOWNLOAD
Download Neural Basis Of Object Motion Perception During Self Motion PDF/ePub or read online books in Mobi eBooks. Click Download or Read Online button to get Neural Basis Of Object Motion Perception During Self Motion book now. This website allows unlimited access to, at the time of writing, more than 1.5 million titles, including hundreds of thousands of titles in various foreign languages. If the content not found or just blank you must refresh this page
Neural Basis Of Object Motion Perception During Self Motion
DOWNLOAD
Author : Nicole E. Peltier
language : en
Publisher:
Release Date : 2020
Neural Basis Of Object Motion Perception During Self Motion written by Nicole E. Peltier and has been published by this book supported file pdf, txt, epub, kindle and other format this book has been release on 2020 with Motion perception (Vision) categories.
"The ability to perceive independently moving objects during self-motion is vital for reaching goals and avoiding obstacles. Self-motion generates a structured pattern of retinal motion called optic flow. An independently moving object produces retinal motion that is the vector sum of its world-relative motion and the optic flow created by the observer's self-motion. To interpret the object's world-relative motion, an observer must compensate for their self-motion. The flow-parsing hypothesis posits that the visual system may accomplish this compensation by globally subtracting out the optic flow due to self-motion (Rushton & Warren, 2005; P.A. Warren & Rushton, 2007, 2009a). This subtraction induces a perceptual bias (in retinal coordinates) away from the optic flow vector at the object's location. Despite psychophysical evidence for flow parsing in humans, the neural mechanisms underlying flow parsing remained unknown. This thesis presents the first evidence for a neural correlate to flow parsing in the middle temporal area (MT). First, we tested the flow-parsing hypothesis in an animal model using macaque monkeys. Two monkeys discriminated the direction of a moving object in the presence of optic flow simulating self-motion. Perception of object motion was biased in a manner consistent with flow parsing. Biases generally depended on the direction and magnitude of the optic flow vectors to subtract at the object's location. The addition of vestibular self-motion cues increased flow-parsing biases in a multiplicative manner. This perceptual evidence of flow parsing in monkeys positioned us to investigate its neural mechanisms. Next, we recorded neural activity in area MT while monkeys performed the same flow-parsing discrimination task. The responses of individual MT units to object motion were modulated by optic flow, and this modulation depended on a unit's direction tuning. We used population decoding to demonstrate that MT populations convey information about choice, retinal object motion, and world-relative object motion. Finally, we characterized the effect of optic flow on MT direction tuning curves by modeling each unit's reference frame as a weighted average of retinal and world-centered. The average MT unit modestly shifted its reference frame from retinal toward world-centered. These small shifts suggest that MT plays a role in a more extensive flow-parsing network"--Pages x-xi
Neural Basis Of Depth Perception From Motion Parallax
DOWNLOAD
Author : HyungGoo R.. Kim
language : en
Publisher:
Release Date : 2013
Neural Basis Of Depth Perception From Motion Parallax written by HyungGoo R.. Kim and has been published by this book supported file pdf, txt, epub, kindle and other format this book has been release on 2013 with Depth perception categories.
"When we move through the world, the motion of objects provides a sufficient cue for depth perception. For accurate depth measurements, the brain needs to resolve the depth-sign of objects (that is, whether the object is near or far relative to fixation). This is no easy task as depth-sign can be ambiguous based solely on visual motion. MT neurons are selective for depth-sign from motion parallax by combining retinal inputs and eye movement signals. We addressed three fundamental questions about how the brain uses motion parallax to code depth information. In the first experiment, we asked whether MT neurons are functionally linked to the perception of depth from motion parallax. Responses were recorded while macaque monkeys judged the depth-sign of visual stimuli containing motion parallax cues. We found that trial-by-trial variability of neural responses was correlated with the animal's perceptual decisions in the discrimination task. Greater responses predicted choices toward the depth preference of the recorded neurons. These results provide evidence that MT neurons may be involved in the perception of depth from motion parallax. In the second study, we investigated the nature of response modulation by eye movements. Direction-dependent modulation by eye movements yields the depth-sign selectivity of MT neurons. Responses of near-preferring neurons are suppressed when the eye moves toward the anti-preferred direction of neuron, whereas responses of far-preferring neurons are suppressed during eye movements toward the preferred direction. This response modulation exhibited both multiplicative and additive components, but the depth-sign selectivity of neurons was predicted only by the multiplicative gain change component. Using computer simulations, we show that a population of gain-modulated MT neurons can compute depth from motion parallax. Movement of an observer produces large background motion. In the third study, we hypothesized that neurons can use a visual consequence of self-motion (dynamic perspective cues) to compute depth-sign from motion parallax. We show that MT neurons can disambiguate depth-sign based on large-field background motion, in the absence of eye movements, and that these depth-sign preferences are correlated with those obtained when the animal is physically translated. MT neurons also contribute to depth perception from binocular disparity. It is likely that both eye movements and large field motion modulate MT responses to binocular images in a systematic way to encode the 3D spatial information of objects. These insights provide a deeper understanding of 3D information processing during navigation"--Pages v-vi.
Perception Control Of Self Motion
DOWNLOAD
Author : Rik Warren
language : en
Publisher: Psychology Press
Release Date : 1990
Perception Control Of Self Motion written by Rik Warren and has been published by Psychology Press this book supported file pdf, txt, epub, kindle and other format this book has been release on 1990 with Psychology categories.
First Published in 1990. Routledge is an imprint of Taylor & Francis, an informa company.
The Perception Of Object Motion During Self Motion
DOWNLOAD
Author : Diederick Christian Niehorster
language : en
Publisher: Open Dissertation Press
Release Date : 2017-01-26
The Perception Of Object Motion During Self Motion written by Diederick Christian Niehorster and has been published by Open Dissertation Press this book supported file pdf, txt, epub, kindle and other format this book has been release on 2017-01-26 with categories.
This dissertation, "The Perception of Object Motion During Self-motion" by Diederick Christian, Niehorster, was obtained from The University of Hong Kong (Pokfulam, Hong Kong) and is being sold pursuant to Creative Commons: Attribution 3.0 Hong Kong License. The content of this dissertation has not been altered in any way. We have altered the formatting in order to facilitate the ease of printing and reading of the dissertation. All rights not granted by the above license are retained by the author. Abstract: When we stand still and do not move our eyes and head, the motion of an object in the world or the absence thereof is directly given by the motion or quiescence of the retinal image. Self-motion through the world however complicates this retinal image. During self-motion, the whole retinal image undergoes coherent global motion, called optic flow. Self-motion therefore causes the retinal motion of objects moving in the world to be confounded by a motion component due to self-motion. How then do we perceive the motion of an object in the world when we ourselves are also moving? Although non-visual information about self-motion, such as provided by efference copies of motor commands and vestibular stimulation, might play a role in this ability, it has recently been shown that the brain possesses a purely visual mechanism that underlies scene-relative object motion perception during self-motion. In the flow parsing hypothesis developed by Rushton and Warren (2005; Warren & Rushton, 2007; 2009b), the brain uses its sensitivity to optic flow to detect and globally remove retinal motion due to self-motion and recover the scene-relative motion of objects. Research into this perceptual ability has so far been of a qualitative nature. In this thesis, I therefore develop a retinal motion nulling paradigm to measure the gain with which the flow parsing mechanism uses the optic flow to remove the self-motion component from an object's retinal motion. I use this paradigm to investigate how accurate scene-relative object motion perception during self-motion can be based on only visual information, whether this flow parsing process depends on a percept of the direction of self-motion and the tuning of flow parsing, i.e., how it is modulated by changes in various stimulus aspects. The results reveal that although adding monocular or binocular depth information to the display to precisely specify the moving object's 3D position in the scene improved the accuracy of flow parsing, the flow parsing gain was never up to the extent required by the scene geometry. Furthermore, the flow parsing gain was lower at higher eccentricities from the focus of expansion in the flow field and was strongly modulated by changes in the motion angle between the self-motion and object motion components in the retinal motion of the moving object, the speeds of these components and the density of the flow field. Lastly, flow parsing was not affected by illusory changes in the perceived direction of self-motion. In conclusion, visual information alone is not sufficient for accurate perception of scene-relative object motion during self-motion. Furthermore, flow parsing takes the 3D position of the moving object in the scene into account and is not a uniform global subtraction process. 8e observed tuning characteristics are different from those of local perceived motion interactions, providing evidence that flow parsing is a separate process from these local motion interactions. Finally, flow parsing does not depend on a prior percept of self-motion direction and instead directly uses the input retinal motion to construct percepts of scene-relative object motion during self-motion. DOI: 10.5353/th_b5177318 Subjects: Motion perception (Vision)
Neural Basis Of Motion Perception For Visual Navigation
DOWNLOAD
Author : Saqib Ishaq Khan
language : en
Publisher:
Release Date : 2010
Neural Basis Of Motion Perception For Visual Navigation written by Saqib Ishaq Khan and has been published by this book supported file pdf, txt, epub, kindle and other format this book has been release on 2010 with categories.
Investigation In Neural Computation And Circuitry Of Human Visual Motion Perception
DOWNLOAD
Author : Javier Omar Garcia
language : en
Publisher:
Release Date : 2009
Investigation In Neural Computation And Circuitry Of Human Visual Motion Perception written by Javier Omar Garcia and has been published by this book supported file pdf, txt, epub, kindle and other format this book has been release on 2009 with categories.
Motion is an important cue in the everyday lives of visual creatures. Motion information facilitates the separation of figure from background, aides in seeing objects that would otherwise be effectively camouflaged and surfaces that would be otherwise imperceptible. The research presented is an investigation of the neural correlates of complex motion stimuli. Experiment 1 is a psychophysical investigation of a complex motion phenomenon, called biological motion. Previous research has shown the resilience of this stimulus under highly degraded conditions, but by creating stimuli that favor the "form system", we measured the reliance of biological motion perception on the "motion system". We challenge form-based biological motion research, and we conclude that motion perception is necessary (but not sufficient) for perceiving biological motion. We conjecture that this insufficiency is due to another mechanism, in addition to those involved in simple motion discriminations. Experiment series 2 is a neuroimaging investigation of biological motion as a function of contrast modulations, which seeks to find the neural correlate of the effect found in Experiment 1. We specifically targeted the human middle temporal complex (hMT+, the motion-sensitive human homologue to monkey MT), a region implicated in motion perception and historically important in neuroscience research. We find the responses in hMT+ to be stimulus-dependent and to be a part of network of brain regions supporting complex motion perception. Experiment series 3 is a neuroimaging investigation of another form of complex motion perception, a phenomenon called motion transparency. When the visual system encounters two overlapping motion vectors, it resolves them by segmenting them into different surfaces (or objects). We attempt to uncover the neural basis of object segmentation defined by motion vectors. We find the hMT to house competing motion vectors with mutual inhibition, including a local competition between motion vectors as well as a global competition between motion-defined surfaces. These results add to the expansive literature on motion processing and depart from a more traditional depiction of the neural underpinnings of motion perception.
On The Perception Of Self Motion
DOWNLOAD
Author : Alessandro Nesti
language : en
Publisher:
Release Date : 2015
On The Perception Of Self Motion written by Alessandro Nesti and has been published by this book supported file pdf, txt, epub, kindle and other format this book has been release on 2015 with Motion perception (Vision) categories.
Everyday life requires humans to move through the environment, while completing crucial tasks such as retrieving nourishment, avoiding perils or controlling motor vehicles. Success in these tasks largely relies in a correct perception of self-motion, i.e. the continuous estimation of one's body position and its derivatives with respect to the world. The processes underlying self-motion perception have fascinated neuroscientists for more than a century and large bodies of neural, behavioural and physiological studies have been conducted to discover how the central nervous system integrates available sensory information to create an internal representation of the physical motion. The goal of this PhD thesis is to extend current knowledge on self-motion perception by focusing on conditions that closely resemble typical aspects of everyday life. In the works conducted within this thesis, I isolate different components typical of everyday life motion and employ psychophysical methodologies to systematically investigate their effect on human self-motion sensitivity. Particular attention is dedicated to the human ability to discriminate between motions of different intensity. How this is achieved has been a fundamental question in the study of perception since the seminal works of Weber and Fechner. When tested over wide ranges of rotations and translations, participants' sensitivity (i.e. their ability to detect motion changes) is found to decrease with increasing motion intensities, revealing a nonlinearity in the perception of self-motion that is not present at the level of ocular reflexes or in neural responses of sensory afferents. The relationship between the stimulus intensity and the smallest intensity change perceivable by the participants can be mathematically described by a power law, regardless on the sensory modality investigated (visual or inertial) and on whether visual and inertial cues were presented alone or congruently combined, such as during natural movements. Individual perceptual law parameters were fit based on experimental data for upward and downward translations and yaw rotations based on visual-only, inertial-only and combined visual-inertial motion cues. Besides wide ranges of motion intensities, everyday life scenarios also provide complex motion patterns involving combinations of rotational and translational motion, visual and inertial sensory cues and physical and mental workload. The question of how different combinations of these factors affect motion sensitivity was experimentally addressed within the framework of driving simulation and revealed that sensitivity might strongly decrease in more realistic conditions, where participants do not only focus on perceiving a 'simple' motion stimulus (e.g. a sinusoidal profile at a specific frequency) but are, instead, actively engaged in a dynamic driving simulation. Applied benefits of the present thesis include advances in the field of vehicle motion simulation, where knowledge on human self-motion perception supports the development of state-of-the-art algorithms to control simulator motion. This allows for reproducing, within a safe and controlled environment, driving or flying experiences that are perceptually realistic to the user. Furthermore, the present work will guide future research into the neural basis of perception and action.
Neural Basis Of Visual Motion Perception
DOWNLOAD
Author : Yunmin Wu
language : en
Publisher:
Release Date : 2019
Neural Basis Of Visual Motion Perception written by Yunmin Wu and has been published by this book supported file pdf, txt, epub, kindle and other format this book has been release on 2019 with categories.
The Senses A Comprehensive Reference
DOWNLOAD
Author :
language : en
Publisher: Academic Press
Release Date : 2020-09-30
The Senses A Comprehensive Reference written by and has been published by Academic Press this book supported file pdf, txt, epub, kindle and other format this book has been release on 2020-09-30 with Medical categories.
The Senses: A Comprehensive Reference, Second Edition, Seven Volume Set is a comprehensive reference work covering the range of topics that constitute current knowledge of the neural mechanisms underlying the different senses. This important work provides the most up-to-date, cutting-edge, comprehensive reference combining volumes on all major sensory modalities in one set. Offering 264 chapters from a distinguished team of international experts, The Senses lays out current knowledge on the anatomy, physiology, and molecular biology of sensory organs, in a collection of comprehensive chapters spanning 4 volumes. Topics covered include the perception, psychophysics, and higher order processing of sensory information, as well as disorders and new diagnostic and treatment methods. Written for a wide audience, this reference work provides students, scholars, medical doctors, as well as anyone interested in neuroscience, a comprehensive overview of the knowledge accumulated on the function of sense organs, sensory systems, and how the brain processes sensory input. As with the first edition, contributions from leading scholars from around the world will ensure The Senses offers a truly international portrait of sensory physiology. The set is the definitive reference on sensory neuroscience and provides the ultimate entry point into the review and original literature in Sensory Neuroscience enabling students and scientists to delve into the subject and deepen their knowledge. All-inclusive coverage of topics: updated edition offers readers the only current reference available covering neurobiology, physiology, anatomy, and molecular biology of sense organs and the processing of sensory information in the brain Authoritative content: world-leading contributors provide readers with a reputable, dynamic and authoritative account of the topics under discussion Comprehensive-style content: in-depth, complex coverage of topics offers students at upper undergraduate level and above full insight into topics under discussion
High Level Motion Processing
DOWNLOAD
Author : Takeo Watanabe
language : en
Publisher: MIT Press
Release Date : 1998
High Level Motion Processing written by Takeo Watanabe and has been published by MIT Press this book supported file pdf, txt, epub, kindle and other format this book has been release on 1998 with Computers categories.
The contributors to this book focus on such key aspects of motion processing as interaction and integration between locally measured motion units, structure from motion, heading in an optical flow, and second-order motion. They also discuss the interaction of motion processing with other high-level visual functions such as surface representation and attention.